Nitride semiconductor device

A nitride semiconductor device includes: a substrate; a first nitride semiconductor layer; a second nitride semiconductor layer; a first opening penetrating through the second nitride semiconductor layer to the first nitride semiconductor layer; a second opening penetrating through the second nitride semiconductor layer to the first nitride semiconductor layer; an electron transport layer and an electron supply layer provided along an inner face of each of the first opening and the second opening and above the second nitride semiconductor layer; a gate electrode; an anode electrode; a third opening penetrating through the electron supply layer and the electron transport layer to the second nitride semiconductor layer; a source electrode in the third opening; a drain electrode; and a cathode electrode. The anode electrode and the source electrode are electrically connected, and the cathode electrode and the drain electrode are electrically connected.